CZ174396A3 - Means for sealing, bonding or coating materials and method of sealing, bonding or coating - Google Patents

Abstract

Compositions for use as sealants, adhesives and/or coatings containing 3,4-polyisoprene and blends of liquid and/or solid rubbers and/or finely divided polymer powders and optionally plasticizers, fillers and other conventional raw materials exhibit superior vibration damping properties compared to conventional compositions not containing 3.4-polyisoprene. The compositions may be cured similar to the conventional sealant/adhesive and/or coating compositions.

Description

The invention relates to novel compositions for gluing p-gaskets containing 3,4-polyisoprenes. More particularly, the present invention relates to vulcanizable and / or non-vulcanizable compositions for bonding, sealing and / or coating materials containing conventional polymeric components and additionally 3,4-polyisoprenes. A preferred field of application for these compositions is the manufacture of vehicles, particularly the automotive industry.

BACKGROUND OF THE INVENTION

In the manufacture and assembly of automobiles, means for sealing or gluing and / or coating materials for many different purposes are used. The means for sealing or gluing is selected mainly on the basis of the following characteristics:

- strength, ie shear strength and adhesion strength

- ductility, flexibility

- durability

2o - ease of application

Abrasion resistance is another criterion for coatings, especially underbody. With a view to reducing the complexity of car production and hence

-2 Production cost reductions are required for 'multifunctional' products, ie means for sealing or gluing and / or coating materials which, in addition to their original function, are also suitable for further use.

Almost exclusively thin sheet metal is used in the design of cars, machinery and equipment. Moving parts and running motors cause these thin metal structures to vibrate, creating noise. Numerous methods for eliminating noise are known, but most require additional manufacturing steps and / or components, the only function of which is noise reduction. A first example for conventional sound attenuation products is high-filled bitumen attenuation linings. These linings must be extruded, cut and shaped in separate steps. Before use, it must often be thermoformed to accommodate uneven structures and then adhere to the body, machine or equipment. Many attempts have been made to replace these even expensive manual processes with products that could easily be applied by robots. In EP-A-358598 or DE-A-3444863, dual-function plastisol compositions have been described as the underbody coating (abrasion protection) and sound damping. DE-A-4013318 discloses a two-layer underbody coating (abrasion protection) and at the same time absorbs noise from impacts (stones, gravel, water, etc.). While these products or processes effectively combine the underbody coating and noise protection functions, there remains a need to combine the adhesive and / or sealant function with noise reduction. This is particularly suitable for those parts of cars, machines or equipment that do not require a special coating to protect against abrasion, such as boot and engine compartment lids, doors or fire barriers.

Adhesives and sealants for these parts are applied in the first stage of production, in the body shop. They are therefore applied to bare, soiled sheets, which are often coated with oil for corrosion protection. Although plastisols, especially PVC plastisols, are used in the body shop, the types described in EP-A-358598 or DE-A-3444863 are not adhesives and

- 3 sealants suitable for plain metal substrate. Plastisol formulations, specially formulated for bare metal application, have poor to no vibration damping properties.

Another class of adhesives and sealants suitable for use in body shops are based on rubbers, particularly vulcanizing agents, based on 1,3-polybutadiene and / or 1,3-polyisoprene. These preferably contain liquid low molecular weight polydienes sulfur and optionally accelerators for sulfur vulcanization. In addition, these compositions may contain solid high molecular weight rubbers, wherein the liquid polydiene (s) and / or the solid rubber may contain functional groups such as hydroxyl groups, carboxyl groups, anhydride groups or epoxy groups. This class of adhesives / sealants has been the subject of various patent applications, for example EP-A-97394, EP-A-309903, DE-A-3834818, DE-A15 4120502, DE-A-4122849, EP-A-181441 and EP-A-181441. A-356715 Although DE-A4122849 and EP-A-181441 refer to the possible use of these vibration and / or noise dampening devices, the effectiveness of these vibration damping devices is not shown here, and to the best of the applicant's knowledge these materials have not been used for their

2O combined adhesive / sealing and vibration damping properties. The use of 3,4-polyisoprene as sealants, adhesives and coatings has thus far not been described.

SUMMARY OF THE INVENTION

According to the present invention, it has been found that 3,4-polyisoprene can be combined with other vulcanizable and / or non-vulcanizable liquid and / or solid rubbers or liquid polyolefins to form adhesive and seal compositions with excellent vibration damping properties. Surprisingly, it has no introduction

3.4- polyisoprene in adhesive and sealing compositions having detrimental effects on other desired properties of the compositions, i.e., deposition ability, vulcanization rate, adhesion, strength and / or elasticity.

In addition to 3,4-polyisoprene, the gluing and sealing means of the present invention may comprise at least one of the following components:

- one or more liquid or solid rubbers or elastomers

- thermoplastic polymers in the form of fine powders

- fillers

tackifiers and / or adhesion promoters

- plasticizers / extenders

- hardeners, accelerators, catalysts is - stabilizers, antioxidants

- substances for improving theological properties.

The 3,4-polyisoprenes of the present invention are polyisoprenes having a significant content of at least 30%, and preferably 55 to 70%, of the 3,420 polyisoprene as determined by NMR spectroscopy. Although advantageous

3.4-polyisoprenes are high molecular weight polymers, i.e. having a molecular weight of 200,000 or more, for some compositions it may be advantageous to use low molecular weight liquid 3,4-polyisoprenes, for example, as additives to conventional plastisols.

The compositions of the invention may contain up to 40% by weight of 3,4-polyispprene, preferably less than 20% by weight of 3,4-polyisoprene, and most preferably 5% by weight to 15% by weight of 3,4-polyisoprene. The sound dampening characteristics can be varied according to the amount of 3,4-polyisoprene added, as evidenced by a corresponding change in the loss factor. Also, to a lesser extent, the effective temperature range in which the loss factor is increased also somewhat depends on the amount of 3,4-polyisoprene added.

Suitable additional liquid rubbers or elastomers may also be selected from the following homo and / or copolymers: polybutadienes, especially 1,3- and 1,2-polybutadienes, which may have terminal and / or side functional groups such as hydroxyl, carboxylic, carboxylic anhydride or epoxy, polybutanes, polyisobutylenes,

1,4-polyisoprenes, styrene-butadiene copolymers, butadiene-15 acrylonitrile copolymers, polyurethanes and polyepoxides. The molecular weight of the liquid rubbers is typically below 20000, preferably between 2000 and 10000. The amount of liquid rubbers in the composition depends on the desired theological properties of the unvulcanized composition and the desired theological properties and sound attenuation of the vulcanized composition. Generally, the amount of liquid rubbers or elastomers varies from about 5 to 50% by weight.

Suitable solid rubbers, which typically have a significantly higher molecular weight than liquid rubbers (100,000 or greater), include polybutadiene (preferably high in cis-1,4-form), styrene-butadiene rubber, butadiene-acrylonitrile rubber, isoprene rubber, butyl rubber and polyurethane rubber.

Examples of thermoplastic polymers are polypropylene, polyethylene, thermoplastic polyurethanes, methacrylate copolymers, styrene copolymers, and PVC.

Fillers can be selected from a wide variety of materials including chalk, calcium carbonate (natural or precipitated), silicate, barite and carbon black. Flaked fillers such as vermiculite, mica, talc or similar layered silicates are also suitable. In some compositions, flake fillers have improved vibration damping efficiency. The total amount of fillers may vary between 10 and 70% by weight with a preferred range of 25 to 60% by weight.

The tackifiers and / or adhesion promoters may include hydrocarbon resins, phenolic resins, as well as terpene phenolic resins, modified and unmodified rosin acids and esters, polyamines, polyaminoamides, polyepoxide resins and anhydrides and copolymers containing anhydride.

The type and amount of tackifier (s) depends on the composition of the polymers of the tackifier and the sealant, the strength of the cured composition, and the substrate to which the tackifier and sealant is applied. Typical tackifiers, such as terpene phenolic resins or rosin derivatives, are usually used in concentrations of about 5 to 20% by weight, and preferably in the range of 7 to 15% by weight. Typical adhesion promoters such as polyamines or polyaminoamides are generally used in the range of about 0.5 to about 10% by weight.

A wide variety of products are used as plasticizers or extenders, including C ₄ -C ₁₄ dialkyl phthalic esters and C ₄ 25 C ₁₄ dialkyl esters of C ₃ -C ₈ dicarboxylic acids, for example, dioctyl adipate, aliphatic, aromatic or naphthenic oils, low molecular weight polybutenes or polyisobutylenes, high boiling liquid hydrocarbons, and mixtures thereof. The rheological properties of the un sounded composition and mechanical properties, including vibration damping, may be influenced to some extent by the amount

- 7 plasticizer or extender. In general, plasticizers / extenders are used in the range of 5 to 40% by weight.

The suitability of hardeners, accelerators or catalysts depends on the reactive and / or functional groups of the selected polymers. A sulfur-based vulcanization system is used to cure olefinic double bonds of liquid or solid rubbers, including 3,4-polyisoprene.

Many organic and inorganic accelerators can be used alone or in combination with powdered sulfur. Examples of such accelerators are mercaptobenzothiazoles, dithiocarbamates, sulfenamides, disulfides such as dibenzothiazole disulfide and / or thiuram disulfides, aldehyde amine accelerators, guanidines and metal oxides such as zinc oxide. In addition, other typical rubber vulcanizing agents such as fatty acids (e.g., stearic acid) may be present in the composition. The amount of sulfur may vary widely from zero (in unvulcanized systems up to about 15%, preferably up to about 10%. Similarly, the amount of accelerator (s) may vary from zero to 10%. The amount of metal oxides ranges from zero to about 10%.

2o Stabilizers may be used against thermal, thermo-oxidative and ozone degradation. They may be selected from conventional stabilizers, such as sterically protected phenols or amines. The amount of stabilizer used is usually in the range of 0.1 to 5% by weight.

Although the rheological properties are normally adjusted by the appropriate type and amount of fillers, conventional additives may be used in an amount ranging from 0.1 to 7% by weight.

Theological properties such as fumed silica or bentonites. In addition, other conventional additives may be present in the formulations.

The acoustic damping performance of the formulations of the invention can be adapted to the particular application needs with respect to the maximum loss factor and the temperature range of the effective loss factor. The decisive parameters are the vulcanization system (the amount of sulfur, with the amount of accelerator) and the rubbers used. To a lesser extent, they also affect the loss factor and the corresponding filler temperature. In addition, the damping factor is influenced by the thickness of the deposited material, while the foam materials have a higher damping factor, but may not be applicable in cases where high tensile strength is required. In most cases, the highest loss factor should be at room temperature (approximately 20 ° C) and a sufficiently high loss factor should be achieved over a wide temperature range. The vulcanization conditions for the adhesive and sealant compositions of the invention may be adapted to the particular application; typically, the vulcanization is carried out at temperatures of 80 to 240 ° C for 10 to 35 minutes.

The present invention may be further illustrated by the following specific examples. As will be readily apparent to one skilled in the art, these examples illustrate various parameters of the present invention, but do not limit the scope thereof in any way, only to the extent that any parameters shown in the examples can be included in the appended claims.

The damping properties (scattering or loss factor) in these examples were determined by the Oberst method (DIN 53440) on steel strips coated with a defined layer of adhesive / sealer and cured in a conventional laboratory oven.

All parts data in the regulations below are parts by weight unless otherwise stated.

Examples of embodiments of the invention

Examples 1-5

The following ingredients were thoroughly mixed in a Z-blade kneader;

1 2 3 4 5 3,4-Polyisoprene ¹ ' 10 10 10 10 10 chalk ² ' 35 31.5 31 31 31 precipitated calcium carbonate ³ ' 24 25 25 25 24 terpene phenolic resin ⁴ ' 10 10 10 10 10 diesel oil ⁵ ' 5 5 5 5 5 polyisobutylene ⁶ ' 15 Dec 15 Dec 15 Dec 15 Dec 15 Dec antioxidant ⁷ ' 1 1 1 1 1 calcium oxide ⁸ ' 0 1 1 1 1 active zinc oxide 0 1 1 1 1 sulfur powder 0 0 0.5 0 1.0 Dibenzothiazole disulfide (MBTS) 0 0.5 0.5 1.0 1.0 Shear strength (MPa) ³ ' 0.6 - - - 1,2

content of 3.4 forms (according to NMR) approximately 60%, Mooney viscosity 65/100 ° C (ML4) natural ground, mean particle size 4.5 µm coated with stearate, mean particle size 0.07 µm

Derophene® T, softening point 93 - 97 ° C (ball and ring)

- 10 'Nyflex® 820, (Nynas-Petroleum) ⁶⁾ Oppahol® B10, (BASF) ⁷⁾ N, N'-di (1,4-dimethylpentyl) -1,4-phenylenediamine ⁸⁾ coated with stearic acid ^a) 2 mm layer between steel discs, vulcanized for 30 min at 155 ° C, breaking the cohesion

Comparative Example 1

By mixing the following ingredients, PVC plastisol was prepared:

pasty PVC emulsion 32.0 d ioctylphtha compounds 30.0 natural ground chalk 16.5 precipitated calcium carbonate 6.0 calcium oxide 3.0 metal oxides (color pigments) 1.0 soot 0.1 stabilizer 1.0 adhesion promoter 2,0 silica 0.4 hydrocarbon extender 8.0

- 11 Example 6 and Comparative Example 2 (cf. 2)

The following ingredients were thoroughly mixed in a Z-blade kneader:

2 6 7 solid rubber ¹⁾ 2.7 - - 3,4-polyisoprene ^{2 '} - 5.0 10.0 liquid polybutadiene ³ ' 8.9 8.9 10.0 liquid polybutadiene ⁴⁾ 17.8 15.5 12.0 carboxylated polybutadiene ^5a) 8.9 8.9 - benzylated polybutadiene ^5b) - - 8.0 precipitated calcium carbonate ⁶⁾ 12.1 12.1 12.1 chalk ⁷ ' 12.1 12.1 12.0 talc 18.6 18.6 21.0 calcium oxide 5.6 5.6 5.5 soot 0.5 0.5 0.1 antioxidant ³ ' 0.5 0.5 0.5 active zinc oxide 4.3 4.3 4.0 sulfur powder 3.0 3.0 2.5 Dibenzothiazole disulfide (MBTS) 5.0 5.0 5.3 Shear strength (MPa) ³ ' 1.4 1.5 1.2 / 2.8

2) high content of cis-3,4 form (98%), Mooney viscosity 68/100 ´C (ML4) content 3,4 of form (by NMR) approximately 60%, Mooney viscosity 65/100 ° C (ML4)

- 12 'molecular weight of approximately 1800, cis-1,4 isomer I content of approximately 72% ⁴⁾ molecular weight of approximately 1800, vinyl content of approximately 40 50% ^5a) polybutadiene / maleic anhydride adduct, molecular weight of approximately 700 ^5b) polybutadiene with terminal benzyl groups, molecular weight approximately 900 ⁵⁾ coated with stearate, mean particle size 0.07 pm ₁₀ ⁷⁾ natural ground, mean particle size 4.5 pm ³⁾ N, N'-di (1,4-dimethylpentyi) -1,4-phenylenediamine ^a) 2 mm layer between steel disks, Comparative Example 2 and Example 6 cured at 155 ° C for 30 min; Example 7 was cured for 30 min at 170 ° C or 30 min at 200 ° C in all cases of cohesion failure

Sound dampening properties

The 240 mm x 10 mm spring steel strips, 1 mm thick, were coated on a 200 mm long section with a layer of the composition described in Examples 1 to 6 and Comparative Examples 1 and 2. The coating thickness is shown below. The coated steel strips were vulcanized in a laboratory oven at 190 ° C for 30 minutes unless otherwise noted. The vulcanized strips were then tested according to the bending vibration test according to DIN 53440 (according to the method according to

Obersta). As can be seen from Figures 1 to 3, mixtures containing 1,4-polyisoprene have a significant damping factor at normal operating temperatures (-10 to 30 ° C), moreover, examples 2 to 5 clearly show that by modifying the vulcanization system, temperature range of the maximum loss factor to the desired area.

Examples 6 and 7 show that the introduction of 3,4-polyisoprene into a conventional vulcanizing sealant and adhesive (Comparative Example 2) substantially improves the damping factor of the vulcanized sealant and adhesive without sacrificing shear strength.

Also, Example 7 clearly shows that a higher vulcanization temperature increases the shear strength of the vulcanized adhesive as expected. Surprisingly, however, the vibration damping as measured by the Oberst method is also increased and, in addition, this increased damping factor is observed over a wider temperature range compared to the composition, even vulcanized at a lower temperature; see comparison of curves 14 and 15 of the figure

3.

Figures 1 to 3 show graphs of the combined loss factor of coated steel strips at 200 Hz versus temperature according to DIN 35440 Part 3. The test strips were prepared as described above. Most samples were prepared with two different coating thicknesses to compensate for normal thickness variations between the different compositions.

Figure 1 shows the loss factor of conventional PVC-plastisol according to Comparative Example 1 (curves 1.2) compared to the compositions according to Example 1 (curves 3.4).

curve means coating thickness 1 comparative example 1 2,27 mm 2 comparative example 1 4,52 mm 3 Example 1 2.2 mm 4 Example 1 4.5 mm

Figure 2 shows how the factor and temperature range over which a significant loss factor (loss factor> 0.1) is observed can be varied by small changes in the composition of the vulcanizing agents.

curve means coating thickness 5 Example 2 2,0 mm 6 Example 2 2,45 mm 7 Example 3 2.6 mm 8 Example 3 3.5 mm 9 Example 4 2,0 mm 10 Example 4 2,65 mm 11 Example 5 4.8 mm

Figure 3 shows that the loss factor of a conventional vulcanized rubber composition according to Comparative Example 2 is insignificant at normal vehicle operating temperatures (-5 ° C to 30 ° C), while the compositions of Examples 6 and 7 io have a significant loss at normal operating temperatures. factor.

curve means coating thickness 12 Example 2 3.0 mm 13 Example 6 3.1 mm 14 Example 7 2.3 mm 15 Dec Example 7 2.3 mm 16 Example 7 4.4 mm

Note: Samples according to curves 15 and 16 were vulcanized for 30 minutes at 200 ° C, while samples according to curve 14 were vulcanized for 30 minutes at 170 ° C.

In addition to their excellent damping properties, all the sealing and adhesive compositions of Examples 1 to 7 had the properties necessary for bodywork applications as sealants and adhesives in the automotive industry.

Represented by:

JUDr. ZDEŇKA KCREJZOVÁ advocate

- 16 10

Claims (5)

PATENT CLAIMS 1. JAi3INiSVIA OHBAmsAwgad avy ci JIIA 8 Z Ol ^ oa Sealing, bonding or coating compositions comprising 5 to 40% by weight of 3,4-polyisoprene, at least one additional liquid or solid rubber, and at least one of the following: fine polymer powders, fillers, hardeners, adhesion promoters, plasticizers and liquid extenders. Compositions according to claim 1, characterized in that the liquid and / or solid rubbers are selected from the group of homo- and / or copolymers of polybutadiene, 1,4-polyisoprene, polyisobutylene, polybutene, styrene-butadiene rubber, polyurethane and polyepoxide. Compositions according to claim 1, characterized in that the hardeners are selected from the group of vulcanizing agents consisting of sulfur and / or an organic accelerator or accelerators, dicyanodiamide, carboxylic acid anhydrides and polyurethane catalysts. Compositions according to claim 1, characterized in that the plasticizers and / or liquid extenders are selected from the group consisting of C ₄ - C ₁₄ dialkyl phthalic acid esters or C ₃ - C ₈ -dicarboxylic acids - 17 acids, aliphatic, aromatic or naphthenic oils, low molecular weight polybutenes or polyisobutylenes and high-boiling liquid hydrocarbons. Compositions as claimed in claim 1, characterized in that the adhesion promoter (s) is selected from the group consisting of hydrocarbon resins, modified and unmodified rosin acids or esters, phenolic resins, terpene as well as phenolic resins, epoxy resins, polyaminoamides, polyamino ether. or polymeric and monomeric carboxylic anhydrides. A method of joining and / or sealing joints between 15 components, characterized in that: - coat at least one of the surfaces of the parts to be joined with the adhesive / seal means according to any one of the preceding claims - parts are assembled The assembled and optionally withdrawn parts are heated to vulcanize the adhesive / seal means. A method of coating components, characterized in that the coating means according to any one of the preceding claims 25 of claims 1 to 5 spray or extrude onto the surface of the component and the coated component is heated to vulcanize the coating. A method for sealing and / or joining and / or coating joints and / or surfaces of components, characterized in that a pre-embossed film, strip or strip made of the composition according to any one of the above is applied to the component. 5 of claims 1 to 5, and the component is optionally heated to vulcanize the composition.